Advanced fragmentation hand grenade

ABSTRACT

A fragmentation structure is provided with improved performance e.g., fragmentation, projectile generation, storage, and manufacturing. An embodiment can include an open fragmentation structure that can be separated into individual components that can include a structure body section with a compartment, a removable initiator or detonator, a top cap section having an aperture configured to accept the removable initiator or removable detonator, and an explosive. An exemplary explosive can be preassembled to fit within the structure without a need for pouring in an explosive. An exemplary structure or top cap of the structure can receive an embrittlement treatment increasing its fragmentation characteristics. An ability of the structure to be easily disassembled allows for safer storage and a longer shelf life. A design of an exemplary embodiment of the structure allows it to be used with a wide range of explosive materials in addition to many types of removable initiators or detonators.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional continuation of and claimspriority to U.S. Patent Application Ser. No. 14/509,386, filed Oct. 8,2014, entitled “ADVANCED FRAGMENTATION HAND GRENADE,” which claimspriority to U.S. Provisional Patent Application Ser. No. 62/020,109,filed Jul. 2, 2014, entitled “ADVANCED FRAGMENTATION HAND GRENADE,” thedisclosures of which are expressly incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The invention described herein was made in the performance of officialduties by employees of the Department of the Navy and may bemanufactured, used and licensed by or for the United States Governmentfor any governmental purpose without payment of any royalties thereon.This invention (Navy Case 200,354) is assigned to the United StatesGovernment and is available for licensing for commercial purposes.Licensing and technical inquiries may be directed to the TechnologyTransfer Office, Naval Surface Warfare Center Crane, email:Cran_CTO@navy.mil.

BACKGROUND AND SUMMARY OF THE INVENTION

The present disclosure relates to hand grenades, and in particularfragmentation hand grenades. Conventional grenades have been in use asanti-personnel weapon for many years and current fragmentation grenadesin use have been regarded as ineffective. Current models offragmentation grenades have also been proven to be inconvenient toproduce and maintain.

An exemplary embodiment of the present disclosure has improvedperformance in terms of fragmentation effects, e.g., lethality,represented by fragmentation number, mass, dispersion, and kineticenergy while still capable of providing traditional form, fit, andfunction of traditional grenades. Additionally, the grenade is improvedthroughout its logistical life cycle as production and maintenance,safety, and processing are improved. The design of an exemplaryembodiment of an advanced fragmentation grenade can allow it to be usedwith a wide range of explosive materials as well as with many types ofremovable detonators depending upon the desired application. Theadvanced fragmentation hand grenade can be separated into individualcomponents that can include an open body section, a top cap section, aremovable detonator, and an explosive. This explosive can bepreassembled to fit within the open body of the grenade. Additionally,the open body of the grenade can receive an embrittlement treatment.

Additional features and advantages of the present invention will becomeapparent to those skilled in the art upon consideration of the followingdetailed description of the illustrative embodiment exemplifying thebest mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to theaccompanying figures in which:

FIG. 1A shows perspective view of an exemplary embodiment of an advancedfragmentation hand grenade;

FIG. 1B shows a side view of an exemplary embodiment of an advancedfragmentation hand grenade;

FIG. 1C shows a cross-sectional view of an exemplary embodiment of anadvanced fragmentation hand grenade;

FIG. 2 shows a perspective view of the open bottom section of anexemplary embodiment of an advanced fragmentation hand grenade;

FIG. 3A shows a top view of the top section of an exemplary embodimentof an advanced fragmentation hand grenade;

FIG. 3B shows a perspective view of the top section of an exemplaryembodiment of an advanced fragmentation hand grenade;

FIG. 4A shows a perspective view of an exemplary embodiment of apreassembled explosive core of an advanced fragmentation hand grenade;

FIG. 4B shows a cross-sectional view of an exemplary embodiment of apreassembled explosive core of an advanced fragmentation hand grenade;

FIG. 5 shows a cross-sectional view of another exemplary embodiment ofan advanced fragmentation grenade; and

FIG. 6 shows an exemplary method of manufacturing an advancedfragmentation hand grenade.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments of the invention described herein are not intended to beexhaustive or to limit the invention to precise forms disclosed. Rather,the embodiments selected for description have been chosen to enable oneskilled in the art to practice the invention.

Referring initially to FIG. 1A, a new advanced fragmentation handgrenade 1 allows for the use of more energetic explosives and optimizesthe position of the grenade fuse. FIG. 1B shows a side view of theadvanced fragmentation hand grenade, which can be comprised of an opengrenade body 3 and a top cap 5. FIG. 1 C shows the cross-section of theadvanced fragmentation hand grenade 1, which can include an open bottomgrenade body 3 that allows for the insertion of a preassembled explosivecore 7 of increased explosive energy. The explosive material can bepressed, cast, extruded or produced by any method and inserted into thegrenade body 3. A preassembled explosive core 7 that can contain adetonator well liner 17 can be inserted into the grenade body 3. Thegrenade body can then be sealed by coupling it with the top cap 5. Finalassembly can be completed by inserting in the removable detonator 9through the top cap 5 and into the preassembled explosive core 7contained in the grenade body 3. The top cap 5 and open grenade body canbe coupled together by press fitting the two components together orthrough other coupling methods (i.e. threated).

As seen in FIG. 2, the grenade body 3 can be hollow in the interior thatallows for easy insertion of a preassembled explosive core 7 or theinsertion of explosive material that can then be pressed, cast, extrudedor produced by any other method. The grenade body 3 can be comprised ofmetal similar to conventional grenades, such as low carbon steel thataids fragmentation. However, the grenade body 3 can receive anembrittlement treatment, for example, through carburizing orcarbonitriding. The embrittlement procedure can include embrittling anopen grenade body by placing the said grenade body into a carbon richand temperature controlled environment, allowing the material to absorbcarbon from the surrounding carbon rich and temperature controlledenvironment, and cooling the material by a cooling agent to harden thegrenade body. The interior or exterior surface of the grenade body 3 andthe top cap 5 can be pre-scored or have a formed fragmentation pattern.

The embrittlement treatment can produce a grenade body that can be bothharder and requires less energy to fragment the grenade body 3. Theresulting fragments will be moving with greater velocity and willdeliver more energy upon impact. The harder fragments will also be lessconsumed by the blast and be of higher mass. This allows for thefragments to have a higher penetrability. The embrittlement treatmentalso provides corrosion resistant properties which can eliminate some ofthe surface coating currently required. The embrittlement process canalso help retain the metal processing advantages of low carbon steel butimproves the fragmentation performance through post formingembrittlement of the grenade body 3. In other embodiments of the presentdisclosure, the top cap 5 can also receive an embattlement treatmentdepending on the desired application and configuration of the top cap 5and grenade body 3.

Referring to FIG. 3A and FIG. 3B, the top cap 5 can include an aperture11 that is capable of accepting the removable detonator 9. The aperturecan be threaded to allow for a threaded removable detonator 9 to ensurestability of the connection between the top cap and the removabledetonator 9. This can allow a user to use different types of initiatingsystems with the hand grenade which can include typical pin detonatorsor remotely operated detonators. The removable detonator 9 increases theversatility of the advanced fragmentation grenade by allowing for a userto change the type of detonator and therefore introducing thepossibility of using alternate initiating systems thereby improving thegrenades usefulness. Additionally, this lowers the maintenance costs ofthe grenade by allowing for a removable detonator and the enclosing theexplosive with any kind of cap in place of the removable detonator.

Referring to FIG. 4A and FIG. 4B, exemplary preassembled explosive core7 can be inserted into a grenade body 3. The explosive core can bemanufactured to have a detonator well 15 near the center of mass of theexplosive for detonating said explosive so as to cause the casing todisintegrate into a plurality of high velocity fragments, where the highexplosive and the casing are configured so that the fragments arepreferentially projected in one or more particular directions relativeto the axis of the grenade body 3. By making the location of theremovable detonator 9 more efficient by placing it near the center massof the preassembled explosive core 7 the velocity and pattern of thefragments are improved.

The detonator well in the preassembled explosive core 7 can also have adetonator well liner 17 isolating the explosive from the environment.The detonator well liner can assist in production and maintenance andwill allow for the use of a removable detonator. A cylindrical portionof the grenade body 3 can be more suitable for adaption to include orgenerate increased external fragments or flechettes to further increaselethality. Early assessments suggest that the position of the detonatorresults in a grenade that can be easier to grip, especially with glovedhands, improving user safety.

FIG. 5 shows another exemplary embodiment of the advanced fragmentationgrenade where the top cap 5 and grenade body 3 are similarly shaped withthe top cap 5 allowing the advanced fragmentation hand grenade tocontain more explosive. While the top cap 5 is identical in shape to thegrenade body 3 it can have a threated aperture 11 to accept a removabledetonator. The top cap 5 and the grenade body 3 can be coupled by pressfitting the two together. Press fitting the top cap 5 and grenade body 3to each other can maximize the fragmentation of the grenade while alsoeliminating a cumbersome step of the manufacturing process.

An ability of an explosive to propel fragments is primarily associatedwith its velocity of detonation. The greater the velocity of thedetonation is, the larger the speed of the projected material in contactwith the explosive. This can be approximated by the Gurney equations.The explosive that can be used in grenades is Composition B (Comp B).Typical grenade bodies are spherical with a single threaded opening.Comp B is melted and poured into the grenade body through this opening.

A velocity of detonation of Comp B can be approximately 7900 m/s. Anexemplary embodiment of the present disclosure can incorporateexplosives with velocities of approximately 110% of Comp B (e.g., i.e.8700 m/s) or possibly even greater. Potential explosives can includePBXN-5, PBXN-9, as well as a version of Composition C4 incorporatingHMX. A limitation to traditional grenade designs is that they require,by design, poured explosives like Comp B. Cast explosives typically havelower detonation velocity. The use of these alternate explosives comesfrom the fact that an exemplary embodiment of this disclosure has beendesigned to enable the use of pressed or extruded explosives with higherdetonation rates. There is additional improvement in individual fragmentkinetic energy initially and at five meters. This can be accomplishedusing the preassembled explosive core 7, which can also increase safetyto the user and environment by helping to eliminate the use of Comp Band incorporating modern Insensitive Munitions (IM) explosives.

A method of manufacturing an advanced fragmentation hand grenade isshown in FIG. 6 and can include:

Step 101: providing a removable detonator adapted to be selectivelyinserted and removed;

Step 103: forming an open grenade body having an interior compartmentadapted to receive the removable detonator and selectively retain andrelease the removable detonator.

Step 105: embrittling said grenade body by placing the grenade body intoa carbon rich and temperature controlled environment, allowing thegrenade body to absorb carbon from the surrounding carbon rich andtemperature controlled environment, and cooling the grenade body by acooling agent to harden the grenade body.

Step 107: forming a top cap having an aperture, wherein the top cap isconfigured to be selectively coupled to the grenade body and theaperture is configured to be selectively coupled to the removabledetonator, wherein the aperture is formed to enable the removabledetonator to be selectively inserted and removed through the top capinto the interior compartment of the grenade body;

Step 109: determining a form and fit of the interior compartment of thegrenade body and the top cap and forming an explosive core so theexplosive core can insert into the interior compartment of theembrittled grenade body and top cap, wherein the explosive core has adetonator well-formed near a center of mass of the preassembledexplosive core;

Step 111: inserting the explosive core into the grenade body.

Step 113: forming the detonator well liner and placing the detonatorwell liner in the detonator well;

Step 115: coupling the top cap to the open grenade body;

Step 117: coupling the removable detonator to the top cap such that saidthe removable detonator is held with a first section extending away fromthe top cap and second portion extending into the detonator well of theexplosive core.

A method, such as discussed in FIG. 6, can be based on components suchas discussed in FIGS. 1-5 or other elements that produce effects orresults associated with the invention.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe spirit and scope of the invention as described and defined in thefollowing claims.

1. An advanced fragmentation device comprising: a device body having aninterior compartment; an explosive core comprised of a quantity ofexplosive material contained within said device body; a coupling sectioncomprising a selective coupling section formed in relation to saiddevice body; a removable detonator near the center of mass of theexplosive core, wherein said removable detonator and explosive core areformed with materials and structure operable for detonating saidexplosive core so as to cause the body to disintegrate into a pluralityof high velocity fragments, where the high explosive and the body areconfigured so that the fragments are projected in a direction relativeto an axis of said device body formed through a longitudinal section ofsaid removable detonator; and a top cap section wherein said top capsection has an aperture adapted to accept said removable detonator;wherein said coupling section is configured to selectively retain saidremovable detonator within said interior compartment.
 2. The advancedfragmentation device of claim 1, wherein the device body is comprised ofembrittled carburized treated low carbon steel.
 3. The advancedfragmentation device of claim 1, wherein the device body is comprised ofembrittled carbonitride treated low carbon steel.
 4. The advancedfragmentation device of claim 1, wherein said coupling section comprisesa threaded section of said aperture.
 5. The advanced fragmentationdevice of claim 1, wherein said explosive core has a detonator wellcovered with a detonator well liner configured to isolate the explosivecore from an outside environment.
 6. The advanced fragmentation deviceof claim 1, wherein said top cap section and device body is configuredto be coupled together by press fitting said top cap section into saiddevice body.
 7. The advanced fragmentation device of claim 1, wherein aninterior or exterior surface of the device body and the top cap arepre-scored or are formed with a fragmentation pattern configured to havea different material strength of other sections of said device body. 8.An advanced fragmentation device comprising: a device body having aninterior compartment comprised of low carbon steel, wherein said devicebody comprised of low carbon steel has a first hardness and firststructural integrity prior to application of an embrittlement processand a second hardness and second structural integrity after applicationof said embrittlement process comprising exposure to a high carbonenvironment and cooling step; an explosive core comprised of a quantityof explosive material contained within said device body, wherein saidexplosive core contains a detonator well near the center of mass of saidexplosive core; a detonator well liner placed inside detonator wellconfigured to isolate the explosive core from an outside environment; atop cap coupled to said device body, wherein said top cap section has anaperture adapted to accept a detonator; and a removable detonatorselectively coupled and retained to said top cap and placed in saiddetonator well near a center of mass of the explosive core fordetonating said explosive core so as to cause the body to disintegrateinto a plurality of high velocity fragments, where the explosive coreand the body are configured so that the fragments are projected in oneor more predetermined directions relative to an axis of said devicebody.
 9. The advanced fragmentation device of claim 8, wherein said topcap and device body are configured to be coupled together by pressfitting said top cap into said device body.
 10. The advancedfragmentation device of claim 8, wherein said top cap and device bodyare configured to be selectively coupled together as well as removableby threated fitting said device body to said top cap.
 11. The advancedfragmentation device of claim 8, wherein said second hardness is harderthan first hardness and said second structural integrity is less thansaid first structural integrity.
 12. The advanced fragmentation deviceof claim 8 wherein said explosive core is comprised of PBXN-9. 13.-19.(canceled)
 20. An advanced fragmentation device comprising: a devicebody having an interior compartment comprised of low carbon steel,wherein said device body comprised of low carbon steel has a firsthardness and first structural integrity prior to application of anembrittlement process and a second hardness and second structuralintegrity after application of said embrittlement process comprisingexposure to a high carbon environment and cooling step; an explosivecore comprised of a quantity of explosive material contained within saiddevice body, wherein said explosive core contains a detonator well nearthe center of mass of said explosive core; a detonator well liner placedinside said detonator well configured to isolate the explosive core froman outside environment; a coupling section comprising a selectivecoupling section formed in relation to said device body; a top capcoupled to said device body, wherein said top cap section has anaperture adapted to accept a detonator; a removable detonatorselectively coupled and retained to said top cap and placed in saiddetonator well near a center of mass of the explosive core fordetonating said explosive core so as to cause the body to disintegrateinto a plurality of high velocity fragments, where the explosive coreand the body are configured so that the fragments are projected in oneor more predetermined directions relative to an axis of said devicebody; wherein said coupling section is configured to selectively retainsaid removable detonator within said interior compartment.
 21. Theadvanced fragmentation device of claim 20, wherein said top cap anddevice body are configured to be coupled together by press fitting saidtop cap into said device body.
 22. The advanced fragmentation device ofclaim 20, wherein said top cap and device body are configured to beselectively coupled together as well as removable by threated fittingsaid device body to said top cap.
 23. The advanced fragmentation deviceof claim 20, wherein said second hardness is harder than said firsthardness and said second structural integrity is less than said firststructural integrity.
 24. The advanced fragmentation device of claim 20,wherein said explosive core is comprised of PBXN-9.
 25. An advancedfragmentation device comprising: a device body having an interiorcompartment comprised of embrittled carburized treated low carbon steel,wherein said device body comprised of embrittled carburized treated lowcarbon steel has a first hardness and first structural integrity priorto application of an embrittlement process and a second hardness andsecond structural integrity after application of said embrittlementprocess comprising exposure to a high carbon environment and coolingstep; an explosive core comprised of a quantity of explosive materialcontained within said device body; a coupling section comprising aselective coupling section formed in relation to said device body; aremovable detonator near the center of mass of the explosive core,wherein said removable detonator and explosive core are formed withmaterials and structure operable for detonating said explosive core soas to cause the body to disintegrate into a plurality of high velocityfragments, where the high explosive and the body are configured so thatthe fragments are projected in a direction relative to an axis of saiddevice body formed through a longitudinal section of said removabledetonator; and a top cap section wherein said top cap section has anaperture adapted to accept said removable detonator; wherein saidcoupling section is configured to selectively retain said removabledetonator within said interior compartment.
 26. The advancedfragmentation device of claim 25, wherein said coupling sectioncomprises a threaded section of said aperture.
 27. The advancedfragmentation device of claim 25, wherein said explosive core has adetonator well covered with a detonator well liner configured to isolatethe explosive core from an outside environment.
 28. The advancedfragmentation device of claim 25, wherein said top cap section anddevice body is configured to be coupled together by press fitting saidtop cap section into said device body.
 29. The advanced fragmentationdevice of claim 25, wherein an interior or exterior surface of thedevice body and the top cap are pre-scored or are formed with afragmentation pattern configured to have a different material strengthof other sections of said device body.
 30. An advanced fragmentationdevice comprising: a device body having an interior compartmentcomprised of embrittled carburized treated low carbon steel, whereinsaid device body comprised of embrittled carburized treated low carbonsteel has a first hardness and first structural integrity prior toapplication of an embrittlement process and a second hardness and secondstructural integrity after application of said embrittlement processcomprising exposure to a high carbon environment and cooling step; anexplosive core comprised of a quantity of explosive material containedwithin said device body; a coupling section comprising a selectivecoupling section formed in relation to said device body; a removabledetonator near the center of mass of the explosive core, wherein saidremovable detonator and explosive core are formed with materials andstructure operable for detonating said explosive core so as to cause thebody to disintegrate into a plurality of high velocity fragments, wherethe high explosive and the body are configured so that the fragments areprojected in a direction relative to an axis of said device body formedthrough a longitudinal section of said removable detonator; and a topcap section wherein said top cap section has an aperture adapted toaccept said removable detonator; wherein said coupling section isconfigured to selectively retain said removable detonator within saidinterior compartment; wherein said coupling section comprises a threadedsection of said aperture; wherein said explosive core has a detonatorwell covered with a detonator well liner configured to isolate theexplosive core from an outside environment; wherein said top cap sectionand said device body is configured to be coupled together by pressfitting said top cap section into said device body; wherein an interioror exterior surface of the device body and the top cap are pre-scored orare formed with a fragmentation pattern configured to have a differentmaterial strength of other sections of said device body.